Ceramic support



Feb. 11, 1941. w sum- 2,231,033

CERAMIC SUPPORT Filed Dec. 6, 1937 2 Sheets-Sheet 1 FIG. I FIG. 3

FIG. 2 FIG. 4

v Will/am FfSmifh INVENTOR ATTORNEY Feb. 11, 1941. w. F. SMITH 2,231,033

CERAMIC SUPPORT Filed Dec. 6, 1937 She ets-Sheet 2 MY/iam ESmifl) INVENTOR ATTORNEY Patented Feb. 11, 1941 UNITED STATES PATENT OFFICE CEBAD ZZ ZSLOFT I William F. Smith, Knoxville, Tenn. V

Application December No. 178,235

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 2 Claims.

The invention herein described may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to the art of firing ceramic ware in kilns and particularly to an feet alignment during firing notwithstanding the presence of internal strains resulting from the process of forming these articles. Another object of this invention is to provide support elements for use in firing a plurality of ceramic flatware articles in order that assemblies containing a large number of these articles may be fired with the production of a maximum number of perfect articles as a result of the firing.

Other objects of this invention include the provision for firing formed ceramic flatware articles in an economical manner on ceramic support elements which may be economically reused by firing successive assemblies of the articles.

Ceramic flatware is easily formed by jiggering or casting from semi-vitreous or hotel china type bodies, but such articles present a difllcult problem in delivering the warev straight from the firing kiln; Deformation in fired ceramic articles is caused for the most part by internal strains arising from one or more of the following sources: characteristics of the plastic body from which the articles are formed, method of forming the ceramic articles, and skill or lack of skill exhibited' during the forming operation. These internal strains are subsequently evidenced, first, during the drying ofthe formed ceramicarticles.

andsecond, during the firing of the dried formed ceramic article's. Kiln placing methods, such used in the manufacture of true porcelain, .Bel

leek,, andpbone'china, result in a satisfactory. product but the kiln capacities areseverelyrehotel china type ware could be employed wherein sand, caicinedkaolin and mixture of calcined.

kaolin and alumina are filled in between the plates. This has not, however, been hitherto" attained particularly in connection with the use of porcelain type ceramic ware. In thehitherto known methods of firing, the processes commonly used do not provide any way for bracing the centers of the ware, which have a tendency to drop if the ware is thin; the processes used do not make it possible to stack the ware to a suiflcient height, say not more than 12 high; the processes used do not appear to overcome strains which are introduced into the ware during the forming operation; the processes used have a tendency to show up the internal strains after a biscuit is fired in spite of the bracing; the materials used for bracing carry an excessive amount of dust; the materials used for bracing considerably affect the translucency of the ware and have a tendency to pack and fuse into the ware; and the materials used for bracing have to be reground or otherwise treated before reuse.

I have discovered a ceramic ware support ele ment for use in a vertically aligned assembly of a plurality of superposed fired ceramic ware support elements and a plurality of unfired ceramic articles in which each article is between two support'elements. The respective ceramic ware support elements are comprised of a ring of uniform thickness with the upper side in a true horizontal plane; a flange integral with the ring, inwardly declined with the upper side of the flangecomplementary to a portion of the reverse of an unfired ceramic article'at the rim of the latter, and the lower side of the flange complementary to a portion of the obverse of another ceramic article in the assembly immediately below the first mentioned ceramic article the arms opposite the flange, with the horizontal upper side of such size and so positioned as to support at least the periphery of the central area of the reverse of the first mentioned ceramic article.

In th e accompanying drawings, which form a part of the specification, and. wherein reference symbols refer to like parts wherever they occur,

Fig. 1 is a plan view of the obverse side of one shape of a formed ceramic article.

Fig. 2 is a vertical section of Fig. 1.

Fig. 3 is a plan view of the obverse side of another shape of a formed ceramic article.

Fig. 4 is a vertical sectional view of Fig. 3.

Fig. 5 is a plan view of the obverse side of a Fig. 11 is a plan view of a fired refractory setter for firing the ceramic article shown in Figs. 3 and 4.

Fig. 12 is a vertical sectional view of Fig. '11.

Fig. 13 is a vertical sectional view of an assembly of the fired ceramic supports as shown in Fig. 6 and Fig. 8, a plurality of formed ceramic articles shown in Figs. 2 and 4, (with only two such articles shown for purposes of illustration),

and a fired refractory setter as shown in Fig. 10

and Fig. 12.

Fig. 14 is a vertical sectional view of the assembly shown in Fig. 13 after firing the ceramic articles to the desired maturity.

In Fig. 1, Fig. 2, Fig. 3, and Fig. 4, formed ceramic articles, represented by ceramic article 2, are shown prepared for firing.

In Fig. 5, Fig. 6, Fig. 7, and Fig. 8, fired ceramic supports, represented by ceramic support 4, are shown ready for assembly prior to firing ceramic articles 2. The fired ceramic support 4, is provided with an outer ring 8, embodying a plurality of pilot stud recesses, represented by pilot stud recess 8, and a plurality of pilot studs, represented by pilot stud l0, allowing inter-engagement of the studs and recesses when the supports are stacked. Adjacent to and integral with the outer ring 6, an inwardly projecting flange i2, is provided. whose upper side I, and'lower side i6, are both inwardly declined corresponding to the reverse and obverse sides, respectively, of the finished ceramic articles. Attached to the flange i2, are a plurality of arms, represented by arm i8, inwardly declined and converging to a center portion 20, which supports the center of the unfired ceramic articles 2.

In Fig. 9, Fig. 10, Fig. 11, and Fig. 12, fired refractory setters, represented by fired refractory setter 22, are shown ready for assembly prior to firing ceramic articles 2.

In Fig. 13, a plurality of unfired ceramic articles 2, as shown in Fig. 2 and Fig. 4, and a plurality of fired ceramic supports 4, as shown in Fig. 6 and Fig. 8, are assembled on a fired refractory setter 22, as shown in Fig. 10 and Fig. 12. The ceramic article 2 rests on the upper side ll of the flange l2 and the center portion 20, of the fired ceramic support I. The lower side l6, of the flange l2, of the fired ceramic support resting on the aforementioned fired ceramic support 4, is complementary to a portion of the obverse side of the unfired ceramic article 2, with suflicient distance between the lower side of the fired ceramic support and the obverse of the unfired ceramic article 2, to be within the tolerance limit of the ceramic article.

In Fig. 14 the lower side I 6, of the flange i2, is shown within substantially the tolerance limit of the fired ceramic article 22, whereby the rim of the ceramic article 2, has been maintained accurately positioned within the tolerance limit throughout the entire firing operation.

It is evident that there are numerous factors which will influence conditions for the most satisfactory operation of my invention. the actual limits of which cannot be established except by a detailed study of each set of raw materials and finished products involved. I

The ceramic support elements are preferably made from a body which will not impart any undesirable discoloration during firing, but. of course this will depend upon the material of the ware being fired, the temperature to which it is fired and the nature of the atmosphere in which it is fired.

The ceramic support elements may be formed by conventional methods such as iiggering or casting. In order, however, that the elements may be uniform to obtain perfect horizontal and vertical alignment during assembly, it is generally necessary to machine a part or all of the respective faces of the. element before firing or after firing in order that the fired support elements prepared for use may have the necessary uniformity.

The support elements used in an assembly for firing a plurality of ceramic articles, should all have substantially the same coefficient of expansion. Furthermore they should be of such a composition that they do not exhibit any appreciable plasticity at the temperature of firing of the ware in order that there be practically no deformation of the supports and consequently provide accurate support for the ware.-

The ceramic flatware articles may be formed by conventional methods, such as jiggering or casting. This invention relates specifically to the support elen'ients used in the production of ceramiclfiatware articles with an exterior edge or rim of any desired shape. This invention is particularly adapted for use in'the production of ceramic flatware articles having intricate design on the obverse and/or rim.

The zones of deformation of a formed ceramic flatware article during firing are first, the center of the article at which gravity probably exerts the most predominate influence, second, the zone through the center line of the foot and third, and by far the most important, the exterior rim of the article where deformation is caused by gravity on the one hand and marked unevenness by the efiect of internal strains in the body of the formed ware on the other hand.

Deformation of ceramic flatware articles during firing can be substantially reduced by firing stacks of flatware articles with their respective zones of most serious deformation, supported by an element which has a central portion of such size and so positioned as to support at least the periphery of .the central area of the reverse of side of the flange and the obverse of the ceramic articlewithin the tolerance limit of the ceramic article. This maintains the ceramic article being fired in positive alignment throughout the entire firing operation.

It is generally desirable to use a true shape refractory setter with its obverse side so shaped as to be complementary to the reverse of one of the ceramic support elements.

In assembling the ceramic support elements and the unfired ceramic ware alternately, the support elements may be vertically aligned in an alignment rack or the support elements may be originally provided with the necessary pilot studs and pilot stud recesses or their equivalent.

It may be necessary to separate the unfired ceramic articles and the support elements from each other, when assembled for firing the former, by the use of a finely divided refractory which is substantially neutral to the body from which these elements are made at the temperature of subsequent firing. A finely divided alumina, such as finer than 150 mesh, has been found suitable for this purpose.

An assembly of ceramic support elements and unfired ceramic articles are fired under conditions of temperature, time and atmosphere to obtain the desired maturity. During the firing there is appreciable shrinkage of all the originally unfired ceramic articles in the assembly with this shrinkage varying considerably with the plastic material from which the articles are formed. They may, for example, vary from 8 to 18%.

After firing the assembly is dismantled and the finely divided refractory adhering to the fired ceramic articles is removed from the articles and the support elements inspected and made available for use in firing subsequent assemblies.

Certain terms used throughout the description and claims are understood to have the following meaning: obverse refers to the top of the article or element as assembled for firing regardless of how the article or element is actually formed and likewise reverse refers to the bottom of the article or element as assembled for firing regardless oi how the article or element is actually formed.

It will be seen, therefore, that this invention actually maybe carried out by the use of various modifications and changes without departing from its spirit and scope, with only such limitations placed thereon as are imposed by the prior art.

I claim:

1. In a vertically aligned assembly of a plurality or superposed fired ceramic ware support elements and a plurality of unfired ceramic articles in which each article is between two support elements, a ceramic ware support element which comprises a continuous outer portion of uniform thickness and substantially uniform width defining a space of greater extent than that odcupied by a ceramic article. said outer portion being contiguous with a like outer portion of a superposed support element; an inwardly declined continuous portion integral with said outer portion for supporting the reverse oi the superposed unfired ceramic article adjacent to the rim of said article; a plurality of spaced inwardly declined arms integral with said declined portion; and a continuous center portion integral with the ends of said arms opposite said outer portion for supporting the central area of the reverse of the ceramic article.

2. In a vertically aligned assembly 01' a'plurality of superposed fired ceramic ware support elements and a plurality oi unfired ceramic articles in which each article is between two support elements, a ceramic ware support element which comprises a continuous outer portion of uniform thickness and substantially uniform width defining a space 01' greater extent than that occupied by a ceramic article, said outer portion being contiguous with like outer portions of a superposed support element and a subjacent support element respectively; an inwardly declined continuous portion integral with said outer portion for supporting the reverse of the superposed unfired ceramic article adjacent to the rim of said article and to maintain the obverse of a subjacent unfired ceramic article adjacent to the rim of said article in positive alignment; a plurality of spaced inwardly declined arms integral with said declined portion; and a continuous center portion integral with the ends of said arms opposite said outer portion for supporting the central area of the reverse of the ceramic article.

WILLIAMF. SMITH. 

